1. Technical Field of the Invention
The invention relates to methods and systems for carrying multiple wireless services using a common distributed antenna system.
2. Description of the Prior Art
Distributed Antenna Systems are used to provide or enhance coverage for wireless services such as Public Safety, Cellular Telephony, Wireless LAN and Medical Telemetry inside buildings and over campuses.
A single DAS can serve a single wireless service (WS) or a combination of many wireless services operating over multiple bands. With respect to medical telemetry services, a medical telemetry system (MTS) access point can be connected to the DAS through the remote wiring closet and using a wireless medical telemetry system (WMTS) module and a service combiner module, the WMTS system can be supported by the DAS using one or more passive antennae.
One desired characteristic of a multi-service DAS is that it can use a single antenna to radiate and receive the signals for all services and frequency bands supported by the DAS. Such an antenna would need to cover (i.e. have acceptable performance) in all frequency bands of interest and is commonly referred to as a Broadband Antenna. An example of a supported frequency range for a DAS antenna would be 400 MHz-6 GHz. To provide MIMO based services, a MIMO antenna which includes multiple antenna elements at a common location can be used.
In referring to the signal flows in DAS systems, the term downlink signal refers to the signal being transmitted by the source transmitter (e.g. cellular base station) through an antenna to the terminals and the term uplink signal refers to the signals being transmitted by the terminals which are received by an antenna and flow to the source receiver. Many wireless services have both an uplink and a downlink, but some have only a downlink (e.g. a mobile video broadcast service) or only an uplink (e.g. certain types of medical telemetry).